


The Little Witch Detective Agency: A Study in Mustard

by TracedInAir



Series: Diakko Week 2020 [3]
Category: Little Witch Academia
Genre: Detective AU, Detective Akko is on the case, Drama, F/F, Internalized Homophobia, Kinda, Sherlock Holmes AU, diakko week 2020, or a woman, or foreign, rainy day, rating will probably get bumped to an M at some point, the 1890s were not a good time to be gay, what could possibly go wrong
Language: English
Status: In-Progress
Published: 2020-08-26
Updated: 2020-09-10
Packaged: 2021-03-06 23:20:33
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,180
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26127148
Author URL: https://archiveofourown.org/users/TracedInAir/pseuds/TracedInAir
Summary: If you have a case that can't be solved, a person that can't be found, a priceless lost item that can't be retrieved, one name is whispered on the streets of London: the Little Witch Detective Agency.More specifically, they whisper of Atsuko Kagari. Famous for being able to make the most incredible deductions off only the smallest pieces of information, Akko's ability to solve crime seems to be, well, almost magical...If only the London Met's latest detective inspector would stop solving all of her cases first!Originally posted as part of Diakko Week 2020, Day 3: Rainy Day.
Relationships: Diana Cavendish/Atsuko "Akko" Kagari
Series: Diakko Week 2020 [3]
Series URL: https://archiveofourown.org/series/1893886
Comments: 23
Kudos: 82





	1. A Rainy Day in London, and Other Uncommon Occurrences

The rain beat down heavily on the roof, almost muffling the sound of the knock at the door. Lotte set down her book with some reluctance, and opened the door to reveal a drenched woman, late fifties, finely dressed despite the weather, with a haughty yet distressed look to her face. “Are you the detectives?” she asked breathlessly.

“That we are, madam,” Lotte said kindly, “welcome to the Little Witch Detective Agency. Why don’t you step in out of the rain, I’ll go put a cup of tea on, and you can explain what the problem is.”

“Oh, thank you,” she said, shuffling inside and taking off her soaking coat.

She walked into the room, and was confronted with the sight of a shorter woman, brown hair hanging behind her head in a loose bun. “Who hurt your children?” Akko said, turning towards her.

“How did you know?” the woman gasped.

“The lines of your face indicate you are a woman used to laughter and love, yet you are currently sick with worry. You have a wedding ring, so you are married, likely with children. As such, I can guess anything that would cause such a happy woman to be distressed would concern her beloved children, am I right, Mrs...?” Akko tilted her head with a winning smile.

“Johnson,” the woman’s face was the very image of shock. “It’s my daughter,” she said, the worry returning, “her wretched, no good layabout of a husband-to-be left her standing at the altar!”

Akko winced sympathetically, “Dreadful as that is ma’am, we’re not in the business of tracking people down for revenge.”

“Revenge would be only the half of it,” Mrs Johnson glared, “what I  _ want _ is my mother’s ring back!”

“He ran off with the ring?” Lotte gasped, setting the teapot on the stove.

“Exactly! We gave it to him to present to my daughter on the best day of her life, and the scoundrel up and vanished!”

“How long ago?” Akko asked, settling into a chair opposite Mrs Johnson.

“Two days. We spoke to the police but they laughed us off, told me to check the pawn shops,” she said.

“Sounds like the Met,” Akko nodded. “You’ve checked his house and work?”

“Work!? We should be so lucky! Michael never worked an honest day in his life, and I wouldn’t care to know the sorts of people he did business with.”

“I see,” Akko tried not to sound frustrated.

“Do you have any of Michael’s possessions?” Lotte asked, bringing Mrs Johnson her cup of tea.

“I should think not!”

“Oh,” Lotte said, sitting down herself. “When did you give him the ring?”

“The very afternoon before the wedding,” Mrs Johnson said. “I didn’t trust him with anything further, and it’s clear even that was more than enough.”

“And do you know where he went after that?” Akko asked.

“How should I know? Likely to the bloody Rose and Crown, as always,” Mrs Johnson sniffed.

“Is there an address we could find him at?”

“He lived on Queen’s Road,” Mrs Johnson said. “Couldn’t tell you which number.”

“Your daughter was to move in with him two days ago, and you don’t know where he lives,” Akko asked, keeping her voice as even as she could manage.

“Would you be able to ask her?” Lotte stepped in.

“Aren’t you detectives? Figure it out!” Mrs Johnson snapped. “I’m hardly going to make my poor stricken daughter think any further about that awful man.”

“Right you are, ma’am,” Akko said, “we’ll get right to it. If you can think of anything else, don’t hesitate to let us know!”

Akko turned to Lotte as soon as Mrs Johnson left. “So we have to search all of London for a man named Michael, who lives on Queen’s Road, and who drinks at the Rose and Crown. Sure narrows things down, huh?”

Lotte smiled apologetically, “Still not as bad as the case with the redhead from Dublin.”

“Don’t remind me,” Akko groaned. “Alright, let’s get moving. Not gonna solve itself!”

* * *

Their shoes sloshed underfoot through the grime of London’s streets. The smog pooled heavily around them, weighed down by the oppressive rain clouds above. Akko could already feel the water starting to seep in through the cheap stitching of her shoes.

Days like this made Akko wish she could afford a really nice set of boots, the kind that cost a whole pound, rather than the couple of shillings she spent on hers. Hell, it probably wouldn’t be long before she’d have spent more than a pound on replacing her crappy shoes anyway. Then she’d be just as broke, but  _ still _ have damp feet.

They weren’t heading to any one of the  _ thirty-one _ Queen’s Roads in London, nor were they heading for whichever Rose and Crown happened to be Michael’s usual haunt. If Mrs Johnson wasn’t going to give them anything to work with, they were going to find it themselves. Such was the thought as they stepped in out of the rain into London’s General Registry Office.

“Hello, we’re looking for the records of marriages within the last three days,” Akko said with a bright smile to the man at the desk.

“Anything more specific?” the man didn’t even look up from his newspaper.

“Well it won’t exactly be a marriage, the groom no-showed,” Akko explained. “But you should have the preliminary paperwork? Names are Michael and uh, Miss Johnson?”

“I’ll have a look,” he got up from his desk with clear reluctance. “Try to give me more to go off next time, eh?”

“Believe me, I wish I was,” Akko said ruefully.

The man disappeared into a back room, and returned a couple of minutes later with a stack of papers. “Got a list of all annulments and cancellations right here… Michael Somethin’ and Miss Johnson, you said?” He flicked through the stack, “Ah, here’s the one. Mr Michael Holborn to be wed to Miss Deborah Johnson on the 27th.”

“Great, thanks!” Akko bowed to the man, who looked at her bemusedly. “Is there an address for Mr Holborn?”

“There might be, why’d I give it to you?” he eyed her suspiciously.

Akko turned to Lotte, who whispered something to her. “Because those files you lost that your boss said he’d kill you if you couldn’t find are at the back of the third storage cupboard, you mis-filed them yesterday.”

“Funny.”

“Go check.”

He did.

“H-how…?” he returned, wide-eyed with disbelief, papers in hand.

“There’s a mark of paint behind your ear, the same colour as the wall behind that cupboard, which was recently repainted. Clearly, you scratched your ear while distracted yesterday, while you misplaced the files,” Akko explained.

“But how did you know they were missing in the bloody first place?” he demanded.

“Your awkward fidgeting. Your desk is in neat order, yet you fidgeted with your paper as if there were something weighing heavily on your mind. Once my partner here saw the paint, the matter explained itself away to us,” Akko smiled.

“You two are truly incredible,” he praised. “You should be detectives, with skills like that. A regular Shiny Chariot and Dr Meirides.”

Akko flushed under the praise, “That is, in fact, why we’re here. We’re looking for Mr Holborn, and the wedding ring he’s run away with.”

The man behind the desk gasped, “No! What villainy!”

“Precisely,” Akko shook her head sadly. “The depths some people will sink to.”

“Terrible times we’re living in miss, what with all these foreigners and all. Oh, excusing yourself of course,” he handed over the wedding registry file.

“Hmm, Michael Holborn, 42A Queen’s Road, Brixton, London,” she looked back to the man. “Thanks very much!”

“No problem at all, miss. Good luck with your case now!”

* * *

“I’m sorry,” Lotte said as they trudged through the rain to Brixton. Of course Michael couldn’t live anywhere nearby, like Marylebone or Covent Garden. Instead, they had to endure at least an hour’s walk through the dreary downpour.

“It’s fine, at least he still helped us out,” Akko kept her chin up in the face of the rain.

“It’s not,” Lotte muttered. “I’m too quiet for him to hear my accent, but you don’t even have that.”

Akko shrugged. “Hardly the worst we’ve had, I’m used to it.”

“You shouldn’t have to be.”

“Eh, I am.”

The silence stretched out as they continued on their way to Brixton. By the time they arrived, they were both thoroughly soaked through from the rain. “42A… 42A…” Akko muttered, walking down Queen’s Road. “Here it is! 42!”

Akko rang the bell, and rapped her knuckles sharply on the door, and waited.

And waited.

“We did expect him to be out,” Lotte said.

“It says 42 _ A _ though, maybe he has a roommate?” Akko said.

They waited a little longer.

“Would be pretty strange to bring your new bride back to a house with a roommate…” Lotte said.

Akko sighed, water sloshing as she waved her arms in frustration. “Well we didn’t walk all this way in the rain for nothing!” She looked up to the window above, “Hmm… maybe I could…?” she made a scampering motion with her hands.

“Absolutely not,” Lotte said, shooting her a glare that was somehow visible through her rain drenched glasses. “He must have a landlord, we’ll start with number 1, and if that fails, ask the neighbours.”

“If the landlord has a cushy place in Kensington or something I’m gonna scream!” Akko wailed.

“Don’t jinx us like that,” Lotte’s face dropped as she rang the bell for number 1.

A minute or so later, the door was opened by a man in his forties with a thin moustache above his lip. “Can I help you?” he asked, with obvious disdain.

“Hello, sir!” Akko stood in front of Lotte, rain falling off her hat in a splash as she bowed. “We were looking for the landlord for this fine street, particularly house number 42A. I don’t suppose you can be of any assistance?”

He sneered at her. “More debt collectors looking for Mr Holborn is it? I’m afraid you’ll have to wait until he pays me the two months’ rent I’m owed. Ta ta, now,” he went to close the door in Akko’s face.

“We’re not debt collectors! We’re detectives! Mr Holborn has gone missing,” Akko explained.

“Good riddance, then,” he sniffed. “Perhaps now I’ll be able to find a tenant who actually pays on time. Good day to you, detectives.”

“Wait! If we find Michael, we’ll also be able to find your missing bottle of champagne!” Akko shouted, wedging her foot in the door.

The door stopped, the landlord’s eyes narrowed at her. “And how do you know that?”

“Well, you presently have the eyes of a man who has recently enjoyed one or two glasses of alcohol, as any man is within his rights on a fine Friday evening such as this. Furthermore, your lips do not have the purple texture of a wine-drinker, yet you are a man of refinement, so clearly not beer or cider. While bourbon or whiskey are possibilities, I detected an air of French to your accent, and surmised you to be a man with a taste for champagne. You claim no love for Michael Holborn, yet a stricter landlord would have evicted him for the first missed payment, never mind the second. So he must have done something to upset you, and recently. He was to be married two days ago, so it strikes me that he must have either borrowed or stolen a bottle of champagne from you for his wedding, and due to his disappearance, has not paid you back,” Akko finished breathlessly. “Am I correct?”

“Supposing you were,” his eyes narrowed further, nose turning up, “it would appear far more likely that you already knew of the missing bottle, likely because Michael tried to sell it to you, or some low-life acquaintance of yours.”

“Believe what you will,” Akko said, raising her hands placatingly, “but we’re your only chance of getting it back.”

He stood in the doorway, glaring at Akko and Lotte for a few moments, before sighing. “Fine,” he snapped, heading into his house. He returned a minute later, with a spare key for number 42. “I assume this is what you want?”

“You are most gracious,” Lotte thanked him, accepting the key.

“Have that back to me within the hour,” he shut the door with a firm click.

* * *

The funny thing about the human mind, Akko had come to realise, was the way in which it rationalised things.

As Lotte opened the door to number 42, she shot Akko a worried glance. She knew that the landlord had figured her out, but that didn’t matter. As she was saying, the  _ way _ the human mind rationalised things, was that when it was presented with an implausible explanation, it always searched for a more plausible one.

If you gave a group of people a completely unexplained mystery, their minds would leap to the most far off reaches to fill it. Loch Ness monsters, aliens, ancient curses and the like. But if you presented them with a mystery which had an explanation that they could not believe,  _ then  _ their rejection of it would always lead them to a more sensible explanation.

It didn’t matter that Michael Holborn’s landlord had figured out she hadn’t actually guessed he was a champagne drinker just by looking at him, Akko knew that.

Lotte gathered a collection of Michael’s possessions, and a spirit emerged, whispering in her ear.

Yes, Akko had realised quite some time ago that it didn’t matter if someone figured out she was bullshitting them. All that mattered is that no one figured out the Little Witch Detective Agency was, in fact, a pair of little witches.

**Notes for the Chapter:**

> Hey so I know this was meant to be for Diakko Week and Diana hasn't even shown up yet. I was gonna do the first 2-3 chapters and post them today, but I'm feeling pretty unwell so I could only finish this one, sorry!
> 
> This IS gonna be a long running multi-chapter fic, and I'll be getting back to it after Diakko Week's done!


	2. The Reading Habits of one Atsuko Kagari

Akko took a deep breath. The time had finally come. She was going to do it.

She was going to fly.

Akko leapt into the air.

Okaa-san caught her before she could land.

“What have I told you about jumping off the wash basket?” she chided. “I’ll trap you under it if you don’t stop.”

“Okaa-san, did you see? I flew!” Akko beamed, as proud as a six-year old could be.

“Yes, dear, it was very impressive,” Okaa-san patted her head as she placed her back on the ground. “Try not to get yourself too dirty, we have an important guest arriving soon.”

“Who is it? Is it the Emperor?” Akko’s parents had never spoken of meeting the Emperor before, but Obaa-san had told her once he was very important now, and Akko couldn’t think of anyone else who was very important, so it must be him.

“Not quite,” Okaa-san smiled. “William-san is a visitor from far away.”

“Wi-ri-yumu-san?” Akko tried and failed to pronounce the strange name. “Is he from Tokyo?”

“Further than that,” Okaa-san laughed gently.

“Kyoto!?” Akko knew Kyoto was very far away indeed, Obaa-san told her it used to be very important but it wasn’t now.

“Even further.”

Akko couldn’t comprehend a person living even further away than _Kyoto._ Wiriyumu-san must be very strange indeed.

He was even stranger than Akko could have possibly expected.

He arrived with Otou-san, and was much taller than him. Akko had never seen someone so tall. And his _hair._ Who had _yellow hair?_ His clothes were very strange too. Akko didn’t even know how to describe them, they looked so different to any clothes she had ever seen before.

She was midway through pondering why it was that his moustache was so bushy, when Wiriyumu-san noticed her.

“Ah, Kon-nee-chee-wa, At-soo-ko-chan,” he nodded his head to her.

That was very strange. Why couldn’t he speak right? Akko could speak better than him, and she was only six! She was about to ask him, when Okaa-san whispered in her ear to greet him back.

“Konnichiwa, Wiriyumu-san!”

* * *

“Your daughter is very spirited,” William noted, seating himself opposite Yoh as Akko attempted to leap off the washbasket again.

“Fank you,” Yoh grimaced at his mispronunciation. His - admittedly modest - English abilities were supposed to be the crux of this deal, and here he was messing it up already.

“Don’t worry, Kagari-san,” William clearly noticed his apprehension. “Your English is much better than my Japanese, I assure you. Why, you’re practically the only merchant I’ve met here who knows more than five words.”

“You are most kind, Gladsworth-san,” Yoh inclined his head.

“Do call me William, my good fellow.”

“As you request, William-san.”

Megumi poured each of them a cup of tea, then kneeled down next to him. William’s legs sprawled out, clearly unused to sitting at a chabudai, as well as a little too large to fit comfortably.

“I must thank your lady wife for the tea,” he smiled graciously to Megumi. “But as I was saying, I see a wonderful opportunity for the both of us, Kagari-san,” he sipped his tea. “The way I see it, the people here are crying out for the kind of goods my company can provide. All we need is a merchant who knows the locals, knows what makes them tick, and can keep things running here on the ground. What do you say?”

It was a good deal. Far better than Yoh and his small shop had any real right to be making, moderate English skill or not. If he had to guess, he’d say that William had probably gone to a few bigger merchants before him, and found them unwilling to work with a gaijin. After over two hundred years without any contact with outsiders, it was taking everybody some time to adjust.

Oh well, their loss.

“I say, when can we start, William-san?” Yoh smiled.

“Capital, old chap, capital!” William set his cup down and clapped his hands loudly. “Ah yes, I’d brought this to sweeten the deal, but since we’ve already got off on such a strong foot, consider it a welcoming gift to our arrangement.”

He pulled out a tightly wrapped scroll, “Just a small sample of what we’ll be able to bring to the people of Chiba together. This book is terrifically popular back in London, so I had one of my fellows translate it. I reckon it’ll catch on like wildfire over here once we get the wording right, what do you say?”

Yoh looked over the characters printed on the outside. Clearly not written by a hand that was used to writing Japanese characters, but it was at least recognisable. “Shiny… Shario? And… Research of Red?”

“Something like that,” William waved off-handedly. “I imagine we’ll be able to get it more accurate before we start mass producing them.”

Akko wandered in from outside, and was looking curiously at the scroll.

“Aha! Seems we have a fan already!” William’s laugh boomed out. “Does your daughter read, Kagari-san?”

“Yes, she reads good,” Yoh and Megumi had made sure Akko learned to read from a young age, Yoh considered literacy a paramount skill for any merchant-to-be.

“Then she should be quite the fan!” William lifted the scroll.

“Atsooko-chan,” he offered the scroll to her. “Yonda?”

Akko took the offered scroll, wonder filling her eyes. “Arigatou gozaimasu, Wiriyamu-san!”

“An inquisitive young girl,” William said. “Clearly has a bright future ahead of her!”

“I hope so, William-san,” Yoh smiled.

* * *

Akko left her parents to their conversation with the strange man from further-away-than-Kyoto. She unrolled the scroll, and her eyes widened when it kept on unrolling for quite a while. Akko had never read anything quite so long before, and she was a little worried at the idea of reading it. What if Wiriyamu-san was annoyed that she couldn’t read all of it? What if he got mad at Otou-san because of that!?

Akko sat herself down with a determined set to her face. She was going to _read_ this scroll and she was going to read it _well!_

Within a paragraph, Akko was completely hooked.

Neither the poor calligraphy nor questionable grammar could stop her from devouring the rest of the scroll. She barely even noticed when Wiriyamu-san left. It was all Okaa-san could do to tear her away from it long enough to eat dinner, and she wolfed down her food in what felt like seconds, desperate to get back to the wonderful adventures of Shiny Chariot and Dr. Meiridies.

Shiny Chariot was so clever! The way she could figure out someone’s whole life just from looking at them! Akko wondered if she could do that too. She looked at Otou-san, narrowing her eyes as she studied him in detail.

Hmmm… his hands were the exact right size to fit over Akko’s head, clearly because he patted her head so much! Therefore, she could deduce that he was a man who loved his daughter very much and liked to pet her on the head! Flawless.

But not just the deductions, the way she was so good at speaking to people! Chariot went out of her way to make everyone happy, even when she was busy solving a nasty murder. And everybody liked her! Even those meanie detectives who got mad at her for making them all look silly for solving the case, they still thought she was cool!

Akko had never wished people would like her more. She had a couple of friends she got along with, and Otou-san and Okaa-san loved her very much. But she wondered what it would be like to be like Chariot, to be so good at understanding people that everyone loved her. Sounded amazing!

But more impressive than either of those… was the _magic._

Right at the end of the first chapter, Dr. Meiridies revealed that Chariot used _magic_ to solve her mysteries. It was done in secret, with Chariot sneaking back to the scene of the crime in the dead of night so that nobody would see her waving her magic wand.

She used magic several more times, including in the climactic showdown with the murderer, where she had to cleverly hide her spell and make it look like the villain had just tripped up. She was so good with her magic! Even if Dr. Meiridies shouted at her after that if she’d messed up, she’d reveal the secret of magic.

The secret of magic! How amazing! Akko wished she could be part of the secret world of magic too!

As soon as she finished the scroll, she started again, right from the beginning. She wished she had more, but until then, this would have to do.

She read with bated breath as Chariot returned to the scene of the crime. Of course, she already knew the killer wouldn’t be there, she’d read this bit just a few hours ago. But it was so good that Akko still felt the same tension Chariot did as she quietly moved through the abandoned house.

 _“Lumière,”_ Chariot whispered on the page.

Akko had a brilliant idea.

She leapt up, dragging the scroll past her bemused parents. She grabbed a stick that had fallen from a tree outside, and read the characters carefully. She had to make sure she got this right, it was a magic spell after all!

 _“Rumiyairu!”_ Akko yelled, waving her tiny little stick as her parents laughed to themselves at her antics.

And watched in awe as wisps of light began to dance in front of Akko’s delighted face.

* * *

Rain sloshed against the door as Akko and Lotte made their way into the Rose and Crown. The five or so regulars paid them little attention, returning to their drinks after a cursory glance. The bartender was wiping a glass with a filthy rag, and narrowed his eyes as soon as she entered.

“Good evening!” Akko announced. Unamused faces turned towards her. “Anybody here know a guy called Michael Holborn?”

“Fuck off,” the bartender took a better look at her face now she’d moved into the light. His own grimace turned ugly, and he spat another word that was significantly worse.

Akko set her jaw.

“Sure, no problem. I mean, I figured you’d want to get your explanation in early as to why a disappeared man was last seen in your bar _before_ we took that information to Scotland Yard but,” Akko shrugged, walking towards the door, “guess not.”

“Now listen here,” the bartender stepped out from behind the counter.

“Actually, I guess you’d have no reason to worry about some coppers visiting anyway,” Akko continued. “After all, this place is _clearly_ up to regulations. All taxes paid of course, and it’s not like anyone would find the rats in your storage anyway.”

“The fookin’ _what?”_ one of the customers slammed his glass on the table, glaring at the bartender.

“Ah, don’t worry about it,” Akko waved him off. “Bitta rat piss in your booze is good for you, builds character.”

As if sensing the mutiny on his hands, the bartender caved. “Michael was it? Was in here a couple nights back, what you need to know?”

So maybe Akko had never _quite_ got the hang of being as universally liked as Shiny Chariot.

She was OK with that.

**Notes for the Chapter:**

> Apologies for the slow update and short chapter, was busy with Diakko Week and a couple other things. Next chapter is nearly done so I might upload it soon, or sit on it for a bit so I can get a chapter or so ahead, we'll see.


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